Conventionally, a step-down converter and a step-up/step-down converter as well as a step-up converter are usually used as a power factor correction (PFC) circuit.
In order to achieve a small and light-weighted converter circuit, a converter circuit is proposed including “a rectification circuit whose input is an AC power source, a first step-up converter circuit connected to the output of the rectification circuit and having at least a first reactor, first switching means and a first diode, a second step-up converter circuit connected to the first step-up converter circuit in parallel and having at least a second reactor, second switching means and a second diode, and a smoothing capacitor connected to outputs of the first step-up converter circuit and the second step-up converter circuit.” (For example, refer to Patent Literature 1)    Patent Literature 1; Japanese Patent No. 2008-86107 (claim 1)